THERMAL MANAGEMENT IN A FAULT TOLERANT PERMANENT MAGNET MACHINE

• US 20100090549A1
• Filed: 10/10/2008
• Published: 04/15/2010
• Est. Priority Date: 10/10/2008
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: El-Refaie, Ayman Mohamed Fawzi, Shah, Manoj Ramprasad, VanDam, Jeremy Daniel, Gerstler, William Dwight, Kern, John Michael, Shen, Xiaochun
• Application Number:
  US12/249,626
• Publication Number:
  US 20100090549A1
• Time in Patent Office: Days
• US Class Current: 310/58
• CPC Class Codes: H02K 15/022 with salient poles or claw-shaped poles
• CPC Class Codes: H02K 21/222 Flywheel magnetos
• CPC Class Codes: H02K 3/24 with channels or ducts for cooling medium between the conductors
• CPC Class Codes: H02K 9/00 Arrangements for cooling or ventilating channels or ducts in parts of the magnetic circuit H02K1/20, H02K1/32; channels or ducts in or between conductors H02K3/22, H02K3/24
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine

Abstract

A PM machine is provided. The PM machine includes a stator including a stator core, wherein the stator core defines multiple step-shaped stator slots. The stator includes multiple fractional-slot concentrated windings wound within the step-shaped stator slots. The stator also includes at least one cooling tube disposed around the windings. The stator further includes a first insulation layer disposed around the cooling tube. The stator also includes a second insulation layer disposed around the first insulation layer. The stator further includes at least one slot wedge configured to close an opening of a respective one of the step-shaped stator slots, wherein the slot wedge is further configured to adjust a leakage inductance in the PM machine. The PM machine also includes a rotor having a rotor core and disposed outside and concentric with the stator, wherein the rotor core includes a laminated back iron structure disposed around multiple magnets.

Claims

1. A permanent magnet machine comprising:

a stator comprising a stator core, the stator core defining a plurality of step-shaped stator slots and comprising;

a plurality of fractional-slot concentrated windings wound within the step-shaped stator slots;

at least one cooling tube disposed around the windings;

a first insulation layer disposed around the cooling tube;

a second insulation layer disposed around the first insulation layer; and

at least one slot wedge configured to close an opening of a respective one of the step-shaped stator slots, the slot wedge being further configured to adjust a leakage inductance in the permanent magnet machine; and

a rotor comprising a rotor core and disposed outside and concentric with the stator, wherein the rotor core comprises a laminated back iron structure disposed around a plurality of magnets.

2. The machine of claim 1, further comprising an epoxy resin configured to attach the cooling tube to the windings.

3. The machine of claim 1, wherein each of the step-shaped stator slots has a two step configuration.

4. The machine of claim 1, wherein the fractional-slot concentrated windings are wound radially inward on a first step of the two step configuration and radially outward on a second step of the two step configuration.

5. The machine of claim 1, wherein the slot wedge comprises an iron epoxy resin.

6. The machine of claim 1, wherein the fractional-slot concentrated windings comprise a plurality of Litz wires.

7. The machine of claim 1, wherein the first insulating layer and the second insulating layer comprise at least one of mica and a polyimide.

8. The machine of claim 1, wherein the magnets are axially segmented.

9. The machine of claim 1, wherein the at least one cooling tube comprises metal, ceramic or a cured resin.

10. The machine of claim 1, further comprising at least one retaining ring disposed around the back iron structure.

11. The machine of claim 10, wherein the retaining ring comprises a material selected from the group consisting of carbon fiber, inconel, carbon steel and combinations thereof.

12. The machine of claim 1, wherein a third insulating layer is disposed around an outer layer of the windings at a location at which the windings exit the stator core.

13. A permanent magnet machine comprising:

a stator comprising a stator core, the stator core defining a plurality of step-shaped stator slots and comprising;

a plurality of fractional-slot concentrated windings wound within the step-shaped stator slots;

a first insulation layer disposed around each turn of the windings;

a second insulation layer disposed around the first insulation layer;

at least one cooling tube disposed between the first insulation layer and the second insulation layer; and

a slot wedge configured to close at least one opening of a respective one of the plurality of stator slots, the slot wedge configured to adjust a leakage inductance in the machine; and

a rotor comprising a rotor core and disposed outside and concentric with the stator, wherein the rotor core comprises a laminated back iron structure around a plurality of magnets.

14. The machine of claim 13, further comprising an epoxy resin configured to attach the first insulation layer to the windings.

15. The machine of claim 13, wherein each of the step-shaped stator slots has a two step configuration.

16. The machine of claim 13, wherein the fractional-slot concentrated windings are wound radially inward on a first step of the two step configuration and radially outward on a second step of the two step configuration.

17. The machine of claim 13, wherein the slot wedge comprises an iron epoxy resin.

18. The machine of claim 13, wherein the fractional-slot concentrated windings comprise a plurality of Litz wires.

19. The machine of claim 13, wherein the first insulating layer and the second insulating layer comprise at least one of mica and a polyimide.

20. The machine of claim 13, wherein a third insulating layer is disposed around an outer layer of the windings at a location at which the windings exit the stator core.

21. A permanent magnet machine comprising:

a stator comprising a stator core defining a plurality of step-shaped stator slots, the stator core comprising;

a plurality of fractional-slot concentrated windings wound within a plurality of stator slots;

a first insulation layer disposed around each turn of the windings;

a second insulation layer disposed around the first insulation layer; and

at least one cooling tube disposed on an exterior side of the second insulation layer; and

a slot wedge configured to close at least one opening of a respective one of the plurality of stator slots, the slot wedge configured to adjust a leakage inductance in the machine; and

a rotor comprising a rotor core and disposed outside and concentric with the stator, wherein the rotor core comprises a laminated back iron structure around a plurality of magnets.

22. The machine of claim 21, further comprising an epoxy resin configured to attach the first insulation layer to the windings.

23. The machine of claim 21, wherein each of the step-shaped stator slots has a two step configuration.

24. The machine of claim 21, wherein the fractional-slot concentrated windings are wound radially inward on a first step of the two step configuration and radially outward on a second step of the two step configuration.

25. The machine of claim 21, wherein the slot wedge comprises an iron epoxy resin.

26. The machine of claim 21, wherein the fractional-slot concentrated windings comprise a plurality of Litz wires.

27. The machine of claim 21, wherein the first insulating layer and the second insulating layer comprise at least one of mica and a polyimide.

28. The machine of claim 21, wherein a third insulating layer is disposed along walls of the stator slots and a fourth insulating layer is disposed around the at least one cooling tube.

29. A method for forming at least one cooling tube in a permanent magnet machine comprising:

using an insert to form at least one cooling tube;

wherein the step of using the insert comprises;

performing vacuum pressure impregnation (VPI) to deposit a resin in a mold and around the insert for attaching a plurality of wires;

curing the resin; and

removing the insert such that the cured resin defines the at least one cooling tube.